Analysis of short-range ordering effect on shear deformation mechanisms of high-entropy alloys TiNbZrV and TiNbZrHf

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Abstract
In this work, a comprehensive modeling of the influence of short-range order on the mechanical properties of body-centered cubic high-entropy ZrTiNbV and ZrTiNbHf alloys under shear deformation using a hybrid molecular dynamics (MD) and Monte Carlo (MC) approach has been carried out. High-entropy alloys (HEA) are a new class of materials produced by mixing four or more elements in approximately equal proportions, providing a unique combination of properties and expanding the capabilities of traditional materials science. In recent years, special attention has been paid to the mechanical properties and deformation mechanisms of high-entropy alloys with a bcc lattice, where screw dislocations, interaction with atoms of various elements and the formation of short-range order, which contributes to the strengthening of the material, play a key role. Bicrystalline models with different degrees of atomic ordering resulting from MD/MC relaxation have been constructed, allowing for both chaotic and clustered elemental distributions. A comparative analysis of structural changes, defect evolution and mechanical properties (in particular, yield strength) under shear has been carried out. It was found that in ZrTiNbV alloy the formation of Nb clusters initiates local phase transformations BCC → HCP and reduces yield strength, whereas for ZrTiNbHf the formation of segregations and nanoclusters effectively prevents grain boundary migration and phase transformations, which leads to a significant increase in strength. The results are consistent with the current understanding of the role of near-order in the hardening of high-entropy materials and demonstrate that targeted control of chemical ordering and grain boundary structure can be an effective tool for optimizing the mechanical properties of high-entropy alloys. The work extends fundamental knowledge of plasticity and fracture mechanisms in multicomponent alloys and opens new perspectives for their application under high mechanical loads and aggressive environments.

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